A weak neurotoxin exhibits synergic effect with cardiotoxins when co-applied to two non-neural cell lines.

A basic peptide with mass weight of 7.597 kDa was isolated and purified from the Naja atra venom by using the combination of ion exchange chromatography and reverse phase high performance liquid chromatography. N-terminal protein sequence determination revealed that this peptide was a weak neurotoxin. Neurotoxicity and cytotoxicity assay were performed. It was noticed that although the analysis of protein sequence did not show it was much more basic, this neurotoxin was eluted out after a cardiotoxin-like basic protein (CLBP). It was also found that, despite of low neurotoxicity, when applied to two non-neural cell lines including K562 cells and K1735-M2 cells, this weak neurotoxin exhibits synergic effects with cardiotoxins, which is firstly reported. It was presumed that the synergic effect might be due to the presence of their common characteristic tertiary structure, three-finger structure. This fact might bring us some new sights about the functions of the un-lethal components in the complex venom system and may help us to understand how the venom really works as an integrative system.